OFFSET
1,1
COMMENTS
The lesser of the two factors is in A002373.
EXAMPLE
We have a(4) = 33 because 33 = 3*11, with 11 - 3 = 2*4, the smallest number with this property. Others are 85 = 5*13, 209 = 11*19, 713 = 23*31, 1073 = 29*37, 3233 = 53*61, ...
MATHEMATICA
f[n_] := Block[{p = 3}, While[ ! PrimeQ[p] || ! PrimeQ[p + 2n], p++ ]; p(p + 2n)]; Table[ f[n], {n, 1, 55}]
Table[#(#+2n)&/@Select[Prime[Range[2, 100]], PrimeQ[#+2n]&, 1], {n, 60}]// Flatten (* Harvey P. Dale, May 26 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Lekraj Beedassy, Jun 05 2003
EXTENSIONS
Edited and extended by Robert G. Wilson v, Jun 07 2003
STATUS
approved